A better way to construct recombinant chromosome lines and their controls

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 827-830 ◽  
Author(s):  
Yang Yen ◽  
P. Stephen Baenziger

Previous procedures to construct chromosome monosomic, substitution, recombinant chromosome lines and their controls underestimated cultivar heterogeneity, which can increase background effects. Modifications are proposed to increase background homogeneity and to eliminate interference of genetic or structural heterogeneity of the target chromosomes in parental populations. To achieve this goal, a single plant or plants of single-seed descendants of disomic, monosomic, and substitution lines should be used as the parents to construct recombinant chromosome lines and the controls (i.e., the recreated disomic recurrent parent and the recreated disomic substitution line). Intracultivar variations can thus be avoided. The mating plan is carefully designed so that the resultant recombinant chromosome lines and their controls will have a similar genetic background. All the resultant lines will share the same cytoplasm and the same target chromosomes or chromosome segments that came from the parent plant(s). Therefore, we are able to largely reduce the heterogeneity in the genetic background, eliminate the potential intracultivar cytoplasm variations, and be free from the structural or genetic heterogeneity of the target chromosome. In addition, the background heterogeneity, if it exists, could be measured by comparing individual control lines.Key words: quantitative trait, cytogenetics, background heterogeneity, aneuploidy, substitution.

Genome ◽  
2003 ◽  
Vol 46 (6) ◽  
pp. 1010-1023 ◽  
Author(s):  
I Matus ◽  
A Corey ◽  
T Filichkin ◽  
P M Hayes ◽  
M I Vales ◽  
...  

The ancestor of barley (Hordeum vulgare subsp. spontaneum) may be a source of novel alleles for crop improvement. We developed a set of recombinant chromosome substitution lines (RCSLs) using an accession of H. vulgare subsp. spontaneum (Caesarea 26-24, from Israel) as the donor and Hordeum vulgare subsp. vulgare 'Harrington' (the North American malting quality standard) as the recurrent parent via two backcrosses to the recurrent parent, followed by six generations of selfing. Here we report (i) the genomic architecture of the RCSLs, as inferred by simple sequence repeat (SSR) markers, and (ii) the effects of H. vulgare subsp. spontaneum genome segment introgressions in terms of three classes of phenotypes: inflorescence yield components, malting quality traits, and domestication traits. Significant differences among the RCSLs were detected for all phenotypes measured. The phenotypic effects of the introgressions were assessed using association analysis, and these were referenced to quantitative trait loci (QTL) reported in the literature. Hordeum vulgare subsp. spontaneum, despite its overall inferior phenotype, contributed some favorable alleles for agronomic and malting quality traits. In most cases, the introgression of the ancestral genome resulted in a loss of desirable phenotypes in the cultivated parent. Although disappointing from a plant breeding perspective, this finding may prove to be a useful tool for gene discovery.Key words: Hordeum vulgare subsp. vulgare, Hordeum vulgare subsp spontaneum, association analysis, QTLs, genetic resources.


Genome ◽  
2011 ◽  
Vol 54 (1) ◽  
pp. 81-89 ◽  
Author(s):  
S. S. Xu ◽  
C. G. Chu ◽  
M. O. Harris ◽  
C. E. Williams

Near-isogenic lines (NILs) are useful for plant genetic and genomic studies. However, the strength of conclusions from such studies depends on the similarity of the NILs’ genetic backgrounds. In this study, we investigated the genetic similarity for a set of NILs developed in the 1990s to study gene-for-gene interactions between wheat ( Triticum aestivum L.) and the Hessian fly ( Mayetiola destructor (Say)), an important pest of wheat. Each of the eight NILs carries a single H resistance gene and was created by successive backcrossing for two to six generations to susceptible T. aestivum ‘Newton’. We generated 256 target region amplification polymorphism (TRAP) markers and used them to calculate genetic similarity, expressed by the Nei and Li (NL) coefficient. Six of the NILs (H3, H5, H6, H9, H11, and H13) had the highly uniform genetic background of Newton, with NL coefficients from 0.97 to 0.99. However, genotypes with H10 or H12 were less similar to Newton, with NL coefficients of 0.86 and 0.93, respectively. Cluster analysis based on NL coefficients and pedigree analysis showed that the genetic similarity between each of the NILs and Newton was affected by both the number of backcrosses and the genetic similarity between Newton and the H gene donors. We thus generated an equation to predict the number of required backcrosses, given varying similarity of donor and recurrent parent. We also investigated whether the genetic residues of the donor parents that remained in the NILs were related to linkage drag. By using a complete set of ‘Chinese Spring’ nullisomic-tetrasomic lines, one third of the TRAP markers that showed polymorphism between the NILs and Newton were assigned to a specific chromosome. All of the assigned markers were located on chromosomes other than the chromosome carrying the H gene, suggesting that the genetic residues detected in this study were not due to linkage drag. Results will aid in the development and use of near-isogenic lines for studies of the functional genomics of wheat.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1158
Author(s):  
Nacer Bellaloui ◽  
Sukumar Saha ◽  
Jennifer L. Tonos ◽  
Jodi A. Scheffler ◽  
Johnie N. Jenkins ◽  
...  

Nutrients, including macronutrients such as Ca, P, K, and Mg, are essential for crop production and seed quality, and for human and animal nutrition and health. Macronutrient deficiencies in soil lead to poor crop nutritional qualities and a low level of macronutrients in cottonseed meal-based products, leading to malnutrition. Therefore, the discovery of novel germplasm with a high level of macronutrients or significant variability in the macronutrient content of crop seeds is critical. To our knowledge, there is no information available on the effects of chromosome or chromosome arm substitution on cottonseed macronutrient content. The objective of this study was to evaluate the effects of chromosome or chromosome arm substitution on the variability and content of the cottonseed macronutrients Ca, K, Mg, N, P, and S in chromosome substitution lines (CS). Nine chromosome substitution lines were grown in two-field experiments at two locations in 2013 in South Carolina, USA, and in 2014 in Mississippi, USA. The controls used were TM-1, the recurrent parent of the CS line, and the cultivar AM UA48. The results showed major variability in macronutrients among CS lines and between CS lines and controls. For example, in South Carolina, the mean values showed that five CS lines (CS-T02, CS-T04, CS-T08sh, CS-B02, and CS-B04) had higher Ca level in seed than controls. Ca levels in these CS lines varied from 1.88 to 2.63 g kg−1 compared with 1.81 and 1.72 g kg−1 for TM-1 and AMUA48, respectively, with CS-T04 having the highest Ca concentration. CS-M08sh exhibited the highest K concentration (14.50 g kg−1), an increase of 29% and 49% over TM-1 and AM UA48, respectively. Other CS lines had higher Mg, P, and S than the controls. A similar trend was found at the MS location. This research demonstrated that chromosome substitution resulted in higher seed macronutrients in some CS lines, and these CS lines with a higher content of macronutrients can be used as a genetic tool towards the identification of desired seed nutrition traits. Also, the CS lines with higher desired macronutrients can be used as parents to breed for improved nutritional quality in Upland cotton, Gossypium hirsutum L., through improvement by the interspecific introgression of desired seed nutrient traits such as Ca, K, P, S, and N. The positive and significant (p ≤ 0.0001) correlation of P with Ca, P with Mg, S with P, and S with N will aid in understanding the relationships between nutrients to improve the fertilizer management program and maintain higher cottonseed nutrient content.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 804
Author(s):  
Me-Sun Kim ◽  
Ju-Young Yang ◽  
Ju-Kyung Yu ◽  
Yi Lee ◽  
Yong-Jin Park ◽  
...  

The primary goals of rice breeding programs are grain quality and yield potential improvement. With the high demand for rice varieties of premium cooking and eating quality, we developed low-amylose content breeding lines crossed with Samgwang and Milkyqueen through the marker-assisted backcross (MABc) breeding program. Trait markers of the SSIIIa gene referring to low-amylose content were identified through an SNP mapping activity, and the markers were applied to select favorable lines for a foreground selection. To rapidly recover the genetic background of Samgwang (recurrent parent genome, RPG), 386 genome-wide markers were used to select BC1F1 and BC2F1 individuals. Seven BC2F1 lines with targeted traits were selected, and the genetic background recovery range varied within 97.4–99.1% of RPG. The amylose content of the selected BC2F2 grains ranged from 12.4–16.8%. We demonstrated the MABc using a trait and genome-wide markers, allowing us to efficiently select lines of a target trait and reduce the breeding cycle effectively. In addition, the BC2F2 lines confirmed by molecular markers in this study can be utilized as parental lines for subsequent breeding programs of high-quality rice for cooking and eating.


2018 ◽  
Vol 46 (2) ◽  
pp. 679-687 ◽  
Author(s):  
Preeyanuch LARKUNTHOD ◽  
Noppawan NOUNJAN ◽  
Jonaliza L SIANGLIW ◽  
Theerayut TOOJINDA ◽  
Jirawat SANITCHON ◽  
...  

Many of the economically important rice cultivars including ‘Khao Dawk Mali 105’ (KDML105) or jasmine rice, one of the world’s famous rice exported from Thailand suffers from drought due to erratic rainfalls and limited irrigation. To improve drought tolerance and reserve genetic background of KDML105, chromosome segment substitution lines (CSSL) containing drought tolerant quantitative trait loci (DT-QTL) has been previously developed by backcrossing between KDML105 and drought tolerant donor, IR58586-F2-CA-143 (DH212). To understand the physiological responses related to drought tolerance in CSSL lines compared to parents, two CSSLs namely CSSL1-16 and CSSL1-18, respectively were used in this study. Twenty-one-d-old hydroponically grown plants were subjected to 20% PEG for 0, 7, 14 d and then recovered from stress for 3 d. The results indicated that CSSL lines especially, CSSL1-16 showed better performance under drought stress compared to their recurrent parent. Drought tolerance superior CSSL1-16 line was indicated by high water status (high relative water content and leaf water potential), good osmotic adjustment, high proline and greater membrane stability. Moreover, this line was able to resume growth after stress recovery whereas other lines/cultivar could not recover. Similarly, drought tolerant donor showed high water status suggesting that well-maintained plant water status was associated with drought tolerant trait. It could be concluded that the highest drought tolerant line was CSSL1-16 followed by DH212, CSSL1-18 and KDML105. It would be interesting to go further into introgressed section in CSSL1-16 to identify potential candidate genes in DT-QTL for breeding drought tolerant rice in the future.


2012 ◽  
Vol 24 (1) ◽  
pp. 210
Author(s):  
L. D. Spate ◽  
B. K. Redel ◽  
K. M. Whitworth ◽  
W. G. Spollen ◽  
S. M. Blake ◽  
...  

In contrast to oocytes matured in vitro, porcine embryos that result from in vivo maturation and fertilization have a high developmental competence and readily make the transition from oocyte to blastocyst. This observation led us to investigate the transcript profile differences between in vivo- and in vitro-matured porcine oocytes. For the in vivo-matured group, oviducts of 3 gilts of similar genetic background were flushed 2 days after detection of standing oestrus. MII oocytes were collected in pools of 10 and snap frozen in liquid nitrogen for RNA isolation. The in vitro-matured oocytes were obtained by euthanizing 3 gilts, again with a similar genetic background and recovering the ovaries. Follicles (2 to 8 mm in size) were aspirated and oocytes with multiple layers of cumulus cells and uniform cytoplasm were placed in M-199 supplemented with LH, FSH and epidermal growth factor for 42 h. Upon maturation, cumulus cells were stripped and the healthy MII oocytes were collected in pools of 10 and snap frozen. Total RNA was extracted from 3 pools of 10 oocytes for both treatments using an All prep DNA/RNA micro isolation kit (Qiagen, Valencia, CA, USA). Complementary DNA was synthesized using oligo (dT′) primed reverse transcriptase with superscript III (Invitrogen, Carlsbad, CA, USA). Second-strand cDNA was synthesized using DNA polymerase I and sequenced using Illumina Genome Analyzer II. All reads were aligned to a custom-built porcine transcriptome. There were over 18 million reads in the 2 maturation groups that tiled to the 34 433-member transcriptome: 1317 transcripts were detected with a P ≤ 0.1 (Students t-test), a minimum of 7 reads in at least 1 of the treatments and ≥2-fold difference. Real-time PCR was used on selected transcripts. Comparative CT Method was used on an IQ real-time PCR system with the Bio–Rad SYBR green mix. Statistical differences were determined using the Proc general linear model procedure of SAS (SAS Institute Inc., Cary, NC) and means separated with a l.s.d. (P ≤ 0.05). The misrepresented transcripts from the sequencing data were also characterized using the functional annotation tool DAVID. Twelve pathways were overrepresented in the in vitro-matured oocytes (the top 4 are pathways to cancer, spliceosome, cell cycle and ubiquitin-mediated proteolysis). Eight pathways were underrepresented in the in vitro-matured oocytes (the top 4 are cytoskeleton regulation, T-cell receptor signaling pathway, ubiquitin-mediated proteolysis and cell cycle). Eight transcripts were selected for real-time PCR. ZP2 was higher in the in vitro-matured oocytes as determined by both sequencing and real time. ATG4, HSP90, UBAP2 and SOX4 were not different, regardless of assay. SLC7A3, MRPS36 and PDHX2 were not different based on sequencing, but based on real-time MRPS36 and PDHX2, were higher in the in vivo group and SLC7A3 was higher in the in vitro group. In conclusion, there is an abundance of misregulated transcripts and altered pathways in in vitro-matured oocytes. This dataset is a tool that may provide clues to improve the in vitro maturation process so that in vitro-matured oocytes will be more like their in vivo-matured counterparts, thus improving developmental competence. Funded by Food for the 21st Century.


2020 ◽  
Vol 133 (12) ◽  
pp. 3287-3297
Author(s):  
Tianzi Lin ◽  
Cong Zhou ◽  
Gaoming Chen ◽  
Jun Yu ◽  
Wei Wu ◽  
...  

Abstract Key message Heterosis QTLs, including qSS7 and qHD8, with dominance effects were identified through GBS and large-scale phenotyping of CSSLs and hybrid F1 populations in a paddy field. Abstract Heterosis has contributed immensely to agricultural production, but its genetic basis is unclear. We evaluated dominance effects by creating two hybrid populations: a B-homo set with a homozygous background and heterozygous chromosomal segments and a B-heter set with a heterozygous background and homozygous segments. This was achieved by crossing a set of 156 backcrossed-derived chromosome segment substitution lines (CSSLs) with their recurrent parent (9311), the male parent of the first super-high-yield hybrid Liangyoupei9 (LYP9), and with the female parent (PA64s) of the hybrid. The CSSLs were subjected to a genotyping-by-sequencing analysis to develop a genetic map of segments introduced from the PA64s. We evaluated the heterotic effects on eight yield-related traits in the hybrid variety and F1 populations in large-scale field experiments over 2 years. Using a linkage map consisting of high-density SNPs, we identified heterosis-associated genes in LYP9. Five candidate genes contributed to the high yield of LYP9, with qSS7 and qHD8 repeatedly detected in both B-hybrid populations. The heterozygous segments harboring qSS7 and qHD8 showed dominance effects that contributed to the heterosis of yield components in the hybrid rice variety Liangyoupei9.


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